///*
// * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
// * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// *
// */
//
//package com.atguigu.src;
//import java.io.*;
//import java.util.*;
//
///**
// * Hash table based implementation of the <tt>Map</tt> interface.  This
// * implementation provides all of the optional map operations, and permits
// * <tt>null</tt> values and the <tt>null</tt> key.  (The <tt>HashMap</tt>
// * class is roughly equivalent to <tt>Hashtable</tt>, except that it is
// * unsynchronized and permits nulls.)  This class makes no guarantees as to
// * the order of the map; in particular, it does not guarantee that the order
// * will remain constant over time.
// *
// * <p>This implementation provides constant-time performance for the basic
// * operations (<tt>get</tt> and <tt>put</tt>), assuming the hash function
// * disperses the elements properly among the buckets.  Iteration over
// * collection views requires time proportional to the "capacity" of the
// * <tt>HashMap</tt> instance (the number of buckets) plus its size (the number
// * of key-value mappings).  Thus, it's very important not to set the initial
// * capacity too high (or the load factor too low) if iteration performance is
// * important.
// *
// * <p>An instance of <tt>HashMap</tt> has two parameters that affect its
// * performance: <i>initial capacity</i> and <i>load factor</i>.  The
// * <i>capacity</i> is the number of buckets in the hash table, and the initial
// * capacity is simply the capacity at the time the hash table is created.  The
// * <i>load factor</i> is a measure of how full the hash table is allowed to
// * get before its capacity is automatically increased.  When the number of
// * entries in the hash table exceeds the product of the load factor and the
// * current capacity, the hash table is <i>rehashed</i> (that is, internal data
// * structures are rebuilt) so that the hash table has approximately twice the
// * number of buckets.
// *
// * <p>As a general rule, the default load factor (.75) offers a good tradeoff
// * between time and space costs.  Higher values decrease the space overhead
// * but increase the lookup cost (reflected in most of the operations of the
// * <tt>HashMap</tt> class, including <tt>get</tt> and <tt>put</tt>).  The
// * expected number of entries in the map and its load factor should be taken
// * into account when setting its initial capacity, so as to minimize the
// * number of rehash operations.  If the initial capacity is greater
// * than the maximum number of entries divided by the load factor, no
// * rehash operations will ever occur.
// *
// * <p>If many mappings are to be stored in a <tt>HashMap</tt> instance,
// * creating it with a sufficiently large capacity will allow the mappings to
// * be stored more efficiently than letting it perform automatic rehashing as
// * needed to grow the table.
// *
// * <p><strong>Note that this implementation is not synchronized.</strong>
// * If multiple threads access a hash map concurrently, and at least one of
// * the threads modifies the map structurally, it <i>must</i> be
// * synchronized externally.  (A structural modification is any operation
// * that adds or deletes one or more mappings; merely changing the value
// * associated with a key that an instance already contains is not a
// * structural modification.)  This is typically accomplished by
// * synchronizing on some object that naturally encapsulates the map.
// *
// * If no such object exists, the map should be "wrapped" using the
// * {@link Collections#synchronizedMap Collections.synchronizedMap}
// * method.  This is best done at creation time, to prevent accidental
// * unsynchronized access to the map:<pre>
// *   Map m = Collections.synchronizedMap(new HashMap(...));</pre>
// *
// * <p>The iterators returned by all of this class's "collection view methods"
// * are <i>fail-fast</i>: if the map is structurally modified at any time after
// * the iterator is created, in any way except through the iterator's own
// * <tt>remove</tt> method, the iterator will throw a
// * {@link ConcurrentModificationException}.  Thus, in the face of concurrent
// * modification, the iterator fails quickly and cleanly, rather than risking
// * arbitrary, non-deterministic behavior at an undetermined time in the
// * future.
// *
// * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
// * as it is, generally speaking, impossible to make any hard guarantees in the
// * presence of unsynchronized concurrent modification.  Fail-fast iterators
// * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
// * Therefore, it would be wrong to write a program that depended on this
// * exception for its correctness: <i>the fail-fast behavior of iterators
// * should be used only to detect bugs.</i>
// *
// * <p>This class is a member of the
// * <a href="{@docRoot}/../technotes/guides/collections/index.html">
// * Java Collections Framework</a>.
// *
// * @param <K> the type of keys maintained by this map
// * @param <V> the type of mapped values
// *
// * @author  Doug Lea
// * @author  Josh Bloch
// * @author  Arthur van Hoff
// * @author  Neal Gafter
// * @see     Object#hashCode()
// * @see     Collection
// * @see     Map
// * @see     TreeMap
// * @see     Hashtable
// * @since   1.2
// */
//
//public class HashMap<K,V>
//    extends AbstractMap<K,V>
//    implements Map<K,V>, Cloneable, Serializable
//{
//
//    /**
//     * The default initial capacity - MUST be a power of two.
//     */
//    static final int DEFAULT_INITIAL_CAPACITY = 16;
//
//    /**
//     * The maximum capacity, used if a higher value is implicitly specified
//     * by either of the constructors with arguments.
//     * MUST be a power of two <= 1<<30.
//     */
//    static final int MAXIMUM_CAPACITY = 1 << 30;
//
//    /**
//     * The load factor used when none specified in constructor.
//     */
//    static final float DEFAULT_LOAD_FACTOR = 0.75f;
//
//    /**
//     * The table, resized as necessary. Length MUST Always be a power of two.
//     */
//    transient Entry<K,V>[] table;
//
//    /**
//     * The number of key-value mappings contained in this map.
//     */
//    transient int size;
//
//    /**
//     * The next size value at which to resize (capacity * load factor).
//     * @serial
//     */
//    int threshold;
//
//    /**
//     * The load factor for the hash table.
//     *
//     * @serial
//     */
//    final float loadFactor;
//
//    /**
//     * The number of times this HashMap has been structurally modified
//     * Structural modifications are those that change the number of mappings in
//     * the HashMap or otherwise modify its internal structure (e.g.,
//     * rehash).  This field is used to make iterators on Collection-views of
//     * the HashMap fail-fast.  (See ConcurrentModificationException).
//     */
//    transient int modCount;
//
//    /**
//     * The default threshold of map capacity above which alternative hashing is
//     * used for String keys. Alternative hashing reduces the incidence of
//     * collisions due to weak hash code calculation for String keys.
//     * <p/>
//     * This value may be overridden by defining the system property
//     * {@code jdk.map.althashing.threshold}. A property value of {@code 1}
//     * forces alternative hashing to be used at all times whereas
//     * {@code -1} value ensures that alternative hashing is never used.
//     */
//    static final int ALTERNATIVE_HASHING_THRESHOLD_DEFAULT = Integer.MAX_VALUE;
//
//    /**
//     * holds values which can't be initialized until after VM is booted.
//     */
//    private static class Holder {
//
//            // Unsafe mechanics
//        /**
//         * Unsafe utilities
//         */
//        static final sun.misc.Unsafe UNSAFE;
//
//        /**
//         * Offset of "final" hashSeed field we must set in readObject() method.
//         */
//        static final long HASHSEED_OFFSET;
//
//        /**
//         * Table capacity above which to switch to use alternative hashing.
//         */
//        static final int ALTERNATIVE_HASHING_THRESHOLD;
//
//        static {
//            String altThreshold = java.security.AccessController.doPrivileged(
//                new sun.security.action.GetPropertyAction(
//                    "jdk.map.althashing.threshold"));
//
//            int threshold;
//            try {
//                threshold = (null != altThreshold)
//                        ? Integer.parseInt(altThreshold)
//                        : ALTERNATIVE_HASHING_THRESHOLD_DEFAULT;
//
//                // disable alternative hashing if -1
//                if (threshold == -1) {
//                    threshold = Integer.MAX_VALUE;
//                }
//
//                if (threshold < 0) {
//                    throw new IllegalArgumentException("value must be positive integer.");
//                }
//            } catch(IllegalArgumentException failed) {
//                throw new Error("Illegal value for 'jdk.map.althashing.threshold'", failed);
//            }
//            ALTERNATIVE_HASHING_THRESHOLD = threshold;
//
//            try {
//                UNSAFE = sun.misc.Unsafe.getUnsafe();
//                HASHSEED_OFFSET = UNSAFE.objectFieldOffset(
//                    HashMap.class.getDeclaredField("hashSeed"));
//            } catch (NoSuchFieldException | SecurityException e) {
//                throw new Error("Failed to record hashSeed offset", e);
//            }
//        }
//    }
//
//    /**
//     * If {@code true} then perform alternative hashing of String keys to reduce
//     * the incidence of collisions due to weak hash code calculation.
//     */
//    transient boolean useAltHashing;
//
//    /**
//     * A randomizing value associated with this instance that is applied to
//     * hash code of keys to make hash collisions harder to find.
//     */
//    transient final int hashSeed = sun.misc.Hashing.randomHashSeed(this);
//
//    /**
//     * Constructs an empty <tt>HashMap</tt> with the specified initial
//     * capacity and load factor.
//     *
//     * @param  initialCapacity the initial capacity
//     * @param  loadFactor      the load factor
//     * @throws IllegalArgumentException if the initial capacity is negative
//     *         or the load factor is nonpositive
//     */
//    public HashMap(int initialCapacity, float loadFactor) {
//        if (initialCapacity < 0)
//            throw new IllegalArgumentException("Illegal initial capacity: " +
//                                               initialCapacity);
//        if (initialCapacity > MAXIMUM_CAPACITY)
//            initialCapacity = MAXIMUM_CAPACITY;
//        if (loadFactor <= 0 || Float.isNaN(loadFactor))
//            throw new IllegalArgumentException("Illegal load factor: " +
//                                               loadFactor);
//
//        // Find a power of 2 >= initialCapacity
//        int capacity = 1;
//        while (capacity < initialCapacity)
//            capacity <<= 1;
//
//        this.loadFactor = loadFactor;
//        threshold = (int)Math.min(capacity * loadFactor, MAXIMUM_CAPACITY + 1);
//        table = new Entry[capacity];
//        useAltHashing = sun.misc.VM.isBooted() &&
//                (capacity >= Holder.ALTERNATIVE_HASHING_THRESHOLD);
//        init();
//    }
//
//    /**
//     * Constructs an empty <tt>HashMap</tt> with the specified initial
//     * capacity and the default load factor (0.75).
//     *
//     * @param  initialCapacity the initial capacity.
//     * @throws IllegalArgumentException if the initial capacity is negative.
//     */
//    public HashMap(int initialCapacity) {
//        this(initialCapacity, DEFAULT_LOAD_FACTOR);
//    }
//
//    /**
//     * Constructs an empty <tt>HashMap</tt> with the default initial capacity
//     * (16) and the default load factor (0.75).
//     */
//    public HashMap() {
//        this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR);
//    }
//
//    /**
//     * Constructs a new <tt>HashMap</tt> with the same mappings as the
//     * specified <tt>Map</tt>.  The <tt>HashMap</tt> is created with
//     * default load factor (0.75) and an initial capacity sufficient to
//     * hold the mappings in the specified <tt>Map</tt>.
//     *
//     * @param   m the map whose mappings are to be placed in this map
//     * @throws  NullPointerException if the specified map is null
//     */
//    public HashMap(Map<? extends K, ? extends V> m) {
//        this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
//                      DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR);
//        putAllForCreate(m);
//    }
//
//    // internal utilities
//
//    /**
//     * Initialization hook for subclasses. This method is called
//     * in all constructors and pseudo-constructors (clone, readObject)
//     * after HashMap has been initialized but before any entries have
//     * been inserted.  (In the absence of this method, readObject would
//     * require explicit knowledge of subclasses.)
//     */
//    void init() {
//    }
//
//    /**
//     * Retrieve object hash code and applies a supplemental hash function to the
//     * result hash, which defends against poor quality hash functions.  This is
//     * critical because HashMap uses power-of-two length hash tables, that
//     * otherwise encounter collisions for hashCodes that do not differ
//     * in lower bits. Note: Null keys always map to hash 0, thus index 0.
//     */
//    final int hash(Object k) {
//        int h = 0;
//        if (useAltHashing) {
//            if (k instanceof String) {
//                return sun.misc.Hashing.stringHash32((String) k);
//            }
//            h = hashSeed;
//        }
//
//        h ^= k.hashCode();
//
//        // This function ensures that hashCodes that differ only by
//        // constant multiples at each bit position have a bounded
//        // number of collisions (approximately 8 at default load factor).
//        h ^= (h >>> 20) ^ (h >>> 12);
//        return h ^ (h >>> 7) ^ (h >>> 4);
//    }
//
//    /**
//     * Returns index for hash code h.
//     */
//    static int indexFor(int h, int length) {
//        return h & (length-1);
//    }
//
//    /**
//     * Returns the number of key-value mappings in this map.
//     *
//     * @return the number of key-value mappings in this map
//     */
//    public int size() {
//        return size;
//    }
//
//    /**
//     * Returns <tt>true</tt> if this map contains no key-value mappings.
//     *
//     * @return <tt>true</tt> if this map contains no key-value mappings
//     */
//    public boolean isEmpty() {
//        return size == 0;
//    }
//
//    /**
//     * Returns the value to which the specified key is mapped,
//     * or {@code null} if this map contains no mapping for the key.
//     *
//     * <p>More formally, if this map contains a mapping from a key
//     * {@code k} to a value {@code v} such that {@code (key==null ? k==null :
//     * key.equals(k))}, then this method returns {@code v}; otherwise
//     * it returns {@code null}.  (There can be at most one such mapping.)
//     *
//     * <p>A return value of {@code null} does not <i>necessarily</i>
//     * indicate that the map contains no mapping for the key; it's also
//     * possible that the map explicitly maps the key to {@code null}.
//     * The {@link #containsKey containsKey} operation may be used to
//     * distinguish these two cases.
//     *
//     * @see #put(Object, Object)
//     */
//    public V get(Object key) {
//        if (key == null)
//            return getForNullKey();
//        Entry<K,V> entry = getEntry(key);
//
//        return null == entry ? null : entry.getValue();
//    }
//
//    /**
//     * Offloaded version of get() to look up null keys.  Null keys map
//     * to index 0.  This null case is split out into separate methods
//     * for the sake of performance in the two most commonly used
//     * operations (get and put), but incorporated with conditionals in
//     * others.
//     */
//    private V getForNullKey() {
//        for (Entry<K,V> e = table[0]; e != null; e = e.next) {
//            if (e.key == null)
//                return e.value;
//        }
//        return null;
//    }
//
//    /**
//     * Returns <tt>true</tt> if this map contains a mapping for the
//     * specified key.
//     *
//     * @param   key   The key whose presence in this map is to be tested
//     * @return <tt>true</tt> if this map contains a mapping for the specified
//     * key.
//     */
//    public boolean containsKey(Object key) {
//        return getEntry(key) != null;
//    }
//
//    /**
//     * Returns the entry associated with the specified key in the
//     * HashMap.  Returns null if the HashMap contains no mapping
//     * for the key.
//     */
//    final Entry<K,V> getEntry(Object key) {
//        int hash = (key == null) ? 0 : hash(key);
//        for (Entry<K,V> e = table[indexFor(hash, table.length)];
//             e != null;
//             e = e.next) {
//            Object k;
//            if (e.hash == hash &&
//                ((k = e.key) == key || (key != null && key.equals(k))))
//                return e;
//        }
//        return null;
//    }
//
//
//    /**
//     * Associates the specified value with the specified key in this map.
//     * If the map previously contained a mapping for the key, the old
//     * value is replaced.
//     *
//     * @param key key with which the specified value is to be associated
//     * @param value value to be associated with the specified key
//     * @return the previous value associated with <tt>key</tt>, or
//     *         <tt>null</tt> if there was no mapping for <tt>key</tt>.
//     *         (A <tt>null</tt> return can also indicate that the map
//     *         previously associated <tt>null</tt> with <tt>key</tt>.)
//     */
//    public V put(K key, V value) {
//        if (key == null)
//            return putForNullKey(value);
//        int hash = hash(key);
//        int i = indexFor(hash, table.length);
//        for (Entry<K,V> e = table[i]; e != null; e = e.next) {
//            Object k;
//            if (e.hash == hash && ((k = e.key) == key || key.equals(k))) {
//                V oldValue = e.value;
//                e.value = value;
//                e.recordAccess(this);
//                return oldValue;
//            }
//        }
//
//        modCount++;
//        addEntry(hash, key, value, i);
//        return null;
//    }
//
//    /**
//     * Offloaded version of put for null keys
//     */
//    private V putForNullKey(V value) {
//        for (Entry<K,V> e = table[0]; e != null; e = e.next) {
//            if (e.key == null) {
//                V oldValue = e.value;
//                e.value = value;
//                e.recordAccess(this);
//                return oldValue;
//            }
//        }
//        modCount++;
//        addEntry(0, null, value, 0);
//        return null;
//    }
//
//    /**
//     * This method is used instead of put by constructors and
//     * pseudoconstructors (clone, readObject).  It does not resize the table,
//     * check for comodification, etc.  It calls createEntry rather than
//     * addEntry.
//     */
//    private void putForCreate(K key, V value) {
//        int hash = null == key ? 0 : hash(key);
//        int i = indexFor(hash, table.length);
//
//        /**
//         * Look for preexisting entry for key.  This will never happen for
//         * clone or deserialize.  It will only happen for construction if the
//         * input Map is a sorted map whose ordering is inconsistent w/ equals.
//         */
//        for (Entry<K,V> e = table[i]; e != null; e = e.next) {
//            Object k;
//            if (e.hash == hash &&
//                ((k = e.key) == key || (key != null && key.equals(k)))) {
//                e.value = value;
//                return;
//            }
//        }
//
//        createEntry(hash, key, value, i);
//    }
//
//    private void putAllForCreate(Map<? extends K, ? extends V> m) {
//        for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
//            putForCreate(e.getKey(), e.getValue());
//    }
//
//    /**
//     * Rehashes the contents of this map into a new array with a
//     * larger capacity.  This method is called automatically when the
//     * number of keys in this map reaches its threshold.
//     *
//     * If current capacity is MAXIMUM_CAPACITY, this method does not
//     * resize the map, but sets threshold to Integer.MAX_VALUE.
//     * This has the effect of preventing future calls.
//     *
//     * @param newCapacity the new capacity, MUST be a power of two;
//     *        must be greater than current capacity unless current
//     *        capacity is MAXIMUM_CAPACITY (in which case value
//     *        is irrelevant).
//     */
//    void resize(int newCapacity) {
//        Entry[] oldTable = table;
//        int oldCapacity = oldTable.length;
//        if (oldCapacity == MAXIMUM_CAPACITY) {
//            threshold = Integer.MAX_VALUE;
//            return;
//        }
//
//        Entry[] newTable = new Entry[newCapacity];
//        boolean oldAltHashing = useAltHashing;
//        useAltHashing |= sun.misc.VM.isBooted() &&
//                (newCapacity >= Holder.ALTERNATIVE_HASHING_THRESHOLD);
//        boolean rehash = oldAltHashing ^ useAltHashing;
//        transfer(newTable, rehash);
//        table = newTable;
//        threshold = (int)Math.min(newCapacity * loadFactor, MAXIMUM_CAPACITY + 1);
//    }
//
//    /**
//     * Transfers all entries from current table to newTable.
//     */
//    void transfer(Entry[] newTable, boolean rehash) {
//        int newCapacity = newTable.length;
//        for (Entry<K,V> e : table) {
//            while(null != e) {
//                Entry<K,V> next = e.next;
//                if (rehash) {
//                    e.hash = null == e.key ? 0 : hash(e.key);
//                }
//                int i = indexFor(e.hash, newCapacity);
//                e.next = newTable[i];
//                newTable[i] = e;
//                e = next;
//            }
//        }
//    }
//
//    /**
//     * Copies all of the mappings from the specified map to this map.
//     * These mappings will replace any mappings that this map had for
//     * any of the keys currently in the specified map.
//     *
//     * @param m mappings to be stored in this map
//     * @throws NullPointerException if the specified map is null
//     */
//    public void putAll(Map<? extends K, ? extends V> m) {
//        int numKeysToBeAdded = m.size();
//        if (numKeysToBeAdded == 0)
//            return;
//
//        /*
//         * Expand the map if the map if the number of mappings to be added
//         * is greater than or equal to threshold.  This is conservative; the
//         * obvious condition is (m.size() + size) >= threshold, but this
//         * condition could result in a map with twice the appropriate capacity,
//         * if the keys to be added overlap with the keys already in this map.
//         * By using the conservative calculation, we subject ourself
//         * to at most one extra resize.
//         */
//        if (numKeysToBeAdded > threshold) {
//            int targetCapacity = (int)(numKeysToBeAdded / loadFactor + 1);
//            if (targetCapacity > MAXIMUM_CAPACITY)
//                targetCapacity = MAXIMUM_CAPACITY;
//            int newCapacity = table.length;
//            while (newCapacity < targetCapacity)
//                newCapacity <<= 1;
//            if (newCapacity > table.length)
//                resize(newCapacity);
//        }
//
//        for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
//            put(e.getKey(), e.getValue());
//    }
//
//    /**
//     * Removes the mapping for the specified key from this map if present.
//     *
//     * @param  key key whose mapping is to be removed from the map
//     * @return the previous value associated with <tt>key</tt>, or
//     *         <tt>null</tt> if there was no mapping for <tt>key</tt>.
//     *         (A <tt>null</tt> return can also indicate that the map
//     *         previously associated <tt>null</tt> with <tt>key</tt>.)
//     */
//    public V remove(Object key) {
//        Entry<K,V> e = removeEntryForKey(key);
//        return (e == null ? null : e.value);
//    }
//
//    /**
//     * Removes and returns the entry associated with the specified key
//     * in the HashMap.  Returns null if the HashMap contains no mapping
//     * for this key.
//     */
//    final Entry<K,V> removeEntryForKey(Object key) {
//        int hash = (key == null) ? 0 : hash(key);
//        int i = indexFor(hash, table.length);
//        Entry<K,V> prev = table[i];
//        Entry<K,V> e = prev;
//
//        while (e != null) {
//            Entry<K,V> next = e.next;
//            Object k;
//            if (e.hash == hash &&
//                ((k = e.key) == key || (key != null && key.equals(k)))) {
//                modCount++;
//                size--;
//                if (prev == e)
//                    table[i] = next;
//                else
//                    prev.next = next;
//                e.recordRemoval(this);
//                return e;
//            }
//            prev = e;
//            e = next;
//        }
//
//        return e;
//    }
//
//    /**
//     * Special version of remove for EntrySet using {@code Map.Entry.equals()}
//     * for matching.
//     */
//    final Entry<K,V> removeMapping(Object o) {
//        if (!(o instanceof Map.Entry))
//            return null;
//
//        Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
//        Object key = entry.getKey();
//        int hash = (key == null) ? 0 : hash(key);
//        int i = indexFor(hash, table.length);
//        Entry<K,V> prev = table[i];
//        Entry<K,V> e = prev;
//
//        while (e != null) {
//            Entry<K,V> next = e.next;
//            if (e.hash == hash && e.equals(entry)) {
//                modCount++;
//                size--;
//                if (prev == e)
//                    table[i] = next;
//                else
//                    prev.next = next;
//                e.recordRemoval(this);
//                return e;
//            }
//            prev = e;
//            e = next;
//        }
//
//        return e;
//    }
//
//    /**
//     * Removes all of the mappings from this map.
//     * The map will be empty after this call returns.
//     */
//    public void clear() {
//        modCount++;
//        Entry[] tab = table;
//        for (int i = 0; i < tab.length; i++)
//            tab[i] = null;
//        size = 0;
//    }
//
//    /**
//     * Returns <tt>true</tt> if this map maps one or more keys to the
//     * specified value.
//     *
//     * @param value value whose presence in this map is to be tested
//     * @return <tt>true</tt> if this map maps one or more keys to the
//     *         specified value
//     */
//    public boolean containsValue(Object value) {
//        if (value == null)
//            return containsNullValue();
//
//        Entry[] tab = table;
//        for (int i = 0; i < tab.length ; i++)
//            for (Entry e = tab[i] ; e != null ; e = e.next)
//                if (value.equals(e.value))
//                    return true;
//        return false;
//    }
//
//    /**
//     * Special-case code for containsValue with null argument
//     */
//    private boolean containsNullValue() {
//        Entry[] tab = table;
//        for (int i = 0; i < tab.length ; i++)
//            for (Entry e = tab[i] ; e != null ; e = e.next)
//                if (e.value == null)
//                    return true;
//        return false;
//    }
//
//    /**
//     * Returns a shallow copy of this <tt>HashMap</tt> instance: the keys and
//     * values themselves are not cloned.
//     *
//     * @return a shallow copy of this map
//     */
//    public Object clone() {
//        HashMap<K,V> result = null;
//        try {
//            result = (HashMap<K,V>)super.clone();
//        } catch (CloneNotSupportedException e) {
//            // assert false;
//        }
//        result.table = new Entry[table.length];
//        result.entrySet = null;
//        result.modCount = 0;
//        result.size = 0;
//        result.init();
//        result.putAllForCreate(this);
//
//        return result;
//    }
//
//    static class Entry<K,V> implements Map.Entry<K,V> {
//        final K key;
//        V value;
//        Entry<K,V> next;
//        int hash;
//
//        /**
//         * Creates new entry.
//         */
//        Entry(int h, K k, V v, Entry<K,V> n) {
//            value = v;
//            next = n;
//            key = k;
//            hash = h;
//        }
//
//        public final K getKey() {
//            return key;
//        }
//
//        public final V getValue() {
//            return value;
//        }
//
//        public final V setValue(V newValue) {
//            V oldValue = value;
//            value = newValue;
//            return oldValue;
//        }
//
//        public final boolean equals(Object o) {
//            if (!(o instanceof Map.Entry))
//                return false;
//            Map.Entry e = (Map.Entry)o;
//            Object k1 = getKey();
//            Object k2 = e.getKey();
//            if (k1 == k2 || (k1 != null && k1.equals(k2))) {
//                Object v1 = getValue();
//                Object v2 = e.getValue();
//                if (v1 == v2 || (v1 != null && v1.equals(v2)))
//                    return true;
//            }
//            return false;
//        }
//
//        public final int hashCode() {
//            return (key==null   ? 0 : key.hashCode()) ^
//                   (value==null ? 0 : value.hashCode());
//        }
//
//        public final String toString() {
//            return getKey() + "=" + getValue();
//        }
//
//        /**
//         * This method is invoked whenever the value in an entry is
//         * overwritten by an invocation of put(k,v) for a key k that's already
//         * in the HashMap.
//         */
//        void recordAccess(HashMap<K,V> m) {
//        }
//
//        /**
//         * This method is invoked whenever the entry is
//         * removed from the table.
//         */
//        void recordRemoval(HashMap<K,V> m) {
//        }
//    }
//
//    /**
//     * Adds a new entry with the specified key, value and hash code to
//     * the specified bucket.  It is the responsibility of this
//     * method to resize the table if appropriate.
//     *
//     * Subclass overrides this to alter the behavior of put method.
//     */
//    void addEntry(int hash, K key, V value, int bucketIndex) {
//        if ((size >= threshold) && (null != table[bucketIndex])) {
//            resize(2 * table.length);
//            hash = (null != key) ? hash(key) : 0;
//            bucketIndex = indexFor(hash, table.length);
//        }
//
//        createEntry(hash, key, value, bucketIndex);
//    }
//
//    /**
//     * Like addEntry except that this version is used when creating entries
//     * as part of Map construction or "pseudo-construction" (cloning,
//     * deserialization).  This version needn't worry about resizing the table.
//     *
//     * Subclass overrides this to alter the behavior of HashMap(Map),
//     * clone, and readObject.
//     */
//    void createEntry(int hash, K key, V value, int bucketIndex) {
//        Entry<K,V> e = table[bucketIndex];
//        table[bucketIndex] = new Entry<>(hash, key, value, e);
//        size++;
//    }
//
//    private abstract class HashIterator<E> implements Iterator<E> {
//        Entry<K,V> next;        // next entry to return
//        int expectedModCount;   // For fast-fail
//        int index;              // current slot
//        Entry<K,V> current;     // current entry
//
//        HashIterator() {
//            expectedModCount = modCount;
//            if (size > 0) { // advance to first entry
//                Entry[] t = table;
//                while (index < t.length && (next = t[index++]) == null)
//                    ;
//            }
//        }
//
//        public final boolean hasNext() {
//            return next != null;
//        }
//
//        final Entry<K,V> nextEntry() {
//            if (modCount != expectedModCount)
//                throw new ConcurrentModificationException();
//            Entry<K,V> e = next;
//            if (e == null)
//                throw new NoSuchElementException();
//
//            if ((next = e.next) == null) {
//                Entry[] t = table;
//                while (index < t.length && (next = t[index++]) == null)
//                    ;
//            }
//            current = e;
//            return e;
//        }
//
//        public void remove() {
//            if (current == null)
//                throw new IllegalStateException();
//            if (modCount != expectedModCount)
//                throw new ConcurrentModificationException();
//            Object k = current.key;
//            current = null;
//            HashMap.this.removeEntryForKey(k);
//            expectedModCount = modCount;
//        }
//    }
//
//    private final class ValueIterator extends HashIterator<V> {
//        public V next() {
//            return nextEntry().value;
//        }
//    }
//
//    private final class KeyIterator extends HashIterator<K> {
//        public K next() {
//            return nextEntry().getKey();
//        }
//    }
//
//    private final class EntryIterator extends HashIterator<Map.Entry<K,V>> {
//        public Map.Entry<K,V> next() {
//            return nextEntry();
//        }
//    }
//
//    // Subclass overrides these to alter behavior of views' iterator() method
//    Iterator<K> newKeyIterator()   {
//        return new KeyIterator();
//    }
//    Iterator<V> newValueIterator()   {
//        return new ValueIterator();
//    }
//    Iterator<Map.Entry<K,V>> newEntryIterator()   {
//        return new EntryIterator();
//    }
//
//
//    // Views
//
//    private transient Set<Map.Entry<K,V>> entrySet = null;
//
//    /**
//     * Returns a {@link Set} view of the keys contained in this map.
//     * The set is backed by the map, so changes to the map are
//     * reflected in the set, and vice-versa.  If the map is modified
//     * while an iteration over the set is in progress (except through
//     * the iterator's own <tt>remove</tt> operation), the results of
//     * the iteration are undefined.  The set supports element removal,
//     * which removes the corresponding mapping from the map, via the
//     * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
//     * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
//     * operations.  It does not support the <tt>add</tt> or <tt>addAll</tt>
//     * operations.
//     */
//    public Set<K> keySet() {
//        Set<K> ks = keySet;
//        return (ks != null ? ks : (keySet = new KeySet()));
//    }
//
//    private final class KeySet extends AbstractSet<K> {
//        public Iterator<K> iterator() {
//            return newKeyIterator();
//        }
//        public int size() {
//            return size;
//        }
//        public boolean contains(Object o) {
//            return containsKey(o);
//        }
//        public boolean remove(Object o) {
//            return HashMap.this.removeEntryForKey(o) != null;
//        }
//        public void clear() {
//            HashMap.this.clear();
//        }
//    }
//
//    /**
//     * Returns a {@link Collection} view of the values contained in this map.
//     * The collection is backed by the map, so changes to the map are
//     * reflected in the collection, and vice-versa.  If the map is
//     * modified while an iteration over the collection is in progress
//     * (except through the iterator's own <tt>remove</tt> operation),
//     * the results of the iteration are undefined.  The collection
//     * supports element removal, which removes the corresponding
//     * mapping from the map, via the <tt>Iterator.remove</tt>,
//     * <tt>Collection.remove</tt>, <tt>removeAll</tt>,
//     * <tt>retainAll</tt> and <tt>clear</tt> operations.  It does not
//     * support the <tt>add</tt> or <tt>addAll</tt> operations.
//     */
//    public Collection<V> values() {
//        Collection<V> vs = values;
//        return (vs != null ? vs : (values = new Values()));
//    }
//
//    private final class Values extends AbstractCollection<V> {
//        public Iterator<V> iterator() {
//            return newValueIterator();
//        }
//        public int size() {
//            return size;
//        }
//        public boolean contains(Object o) {
//            return containsValue(o);
//        }
//        public void clear() {
//            HashMap.this.clear();
//        }
//    }
//
//    /**
//     * Returns a {@link Set} view of the mappings contained in this map.
//     * The set is backed by the map, so changes to the map are
//     * reflected in the set, and vice-versa.  If the map is modified
//     * while an iteration over the set is in progress (except through
//     * the iterator's own <tt>remove</tt> operation, or through the
//     * <tt>setValue</tt> operation on a map entry returned by the
//     * iterator) the results of the iteration are undefined.  The set
//     * supports element removal, which removes the corresponding
//     * mapping from the map, via the <tt>Iterator.remove</tt>,
//     * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
//     * <tt>clear</tt> operations.  It does not support the
//     * <tt>add</tt> or <tt>addAll</tt> operations.
//     *
//     * @return a set view of the mappings contained in this map
//     */
//    public Set<Map.Entry<K,V>> entrySet() {
//        return entrySet0();
//    }
//
//    private Set<Map.Entry<K,V>> entrySet0() {
//        Set<Map.Entry<K,V>> es = entrySet;
//        return es != null ? es : (entrySet = new EntrySet());
//    }
//
//    private final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
//        public Iterator<Map.Entry<K,V>> iterator() {
//            return newEntryIterator();
//        }
//        public boolean contains(Object o) {
//            if (!(o instanceof Map.Entry))
//                return false;
//            Map.Entry<K,V> e = (Map.Entry<K,V>) o;
//            Entry<K,V> candidate = getEntry(e.getKey());
//            return candidate != null && candidate.equals(e);
//        }
//        public boolean remove(Object o) {
//            return removeMapping(o) != null;
//        }
//        public int size() {
//            return size;
//        }
//        public void clear() {
//            HashMap.this.clear();
//        }
//    }
//
//    /**
//     * Save the state of the <tt>HashMap</tt> instance to a stream (i.e.,
//     * serialize it).
//     *
//     * @serialData The <i>capacity</i> of the HashMap (the length of the
//     *             bucket array) is emitted (int), followed by the
//     *             <i>size</i> (an int, the number of key-value
//     *             mappings), followed by the key (Object) and value (Object)
//     *             for each key-value mapping.  The key-value mappings are
//     *             emitted in no particular order.
//     */
//    private void writeObject(ObjectOutputStream s)
//        throws IOException
//    {
//        Iterator<Map.Entry<K,V>> i =
//            (size > 0) ? entrySet0().iterator() : null;
//
//        // Write out the threshold, loadfactor, and any hidden stuff
//        s.defaultWriteObject();
//
//        // Write out number of buckets
//        s.writeInt(table.length);
//
//        // Write out size (number of Mappings)
//        s.writeInt(size);
//
//        // Write out keys and values (alternating)
//        if (size > 0) {
//            for(Map.Entry<K,V> e : entrySet0()) {
//                s.writeObject(e.getKey());
//                s.writeObject(e.getValue());
//            }
//        }
//    }
//
//    private static final long serialVersionUID = 362498820763181265L;
//
//    /**
//     * Reconstitute the {@code HashMap} instance from a stream (i.e.,
//     * deserialize it).
//     */
//    private void readObject(ObjectInputStream s)
//         throws IOException, ClassNotFoundException
//    {
//        // Read in the threshold (ignored), loadfactor, and any hidden stuff
//        s.defaultReadObject();
//        if (loadFactor <= 0 || Float.isNaN(loadFactor))
//            throw new InvalidObjectException("Illegal load factor: " +
//                                               loadFactor);
//
//        // set hashSeed (can only happen after VM boot)
//        Holder.UNSAFE.putIntVolatile(this, Holder.HASHSEED_OFFSET,
//                sun.misc.Hashing.randomHashSeed(this));
//
//        // Read in number of buckets and allocate the bucket array;
//        s.readInt(); // ignored
//
//        // Read number of mappings
//        int mappings = s.readInt();
//        if (mappings < 0)
//            throw new InvalidObjectException("Illegal mappings count: " +
//                                               mappings);
//
//        int initialCapacity = (int) Math.min(
//                // capacity chosen by number of mappings
//                // and desired load (if >= 0.25)
//                mappings * Math.min(1 / loadFactor, 4.0f),
//                // we have limits...
//                HashMap.MAXIMUM_CAPACITY);
//        int capacity = 1;
//        // find smallest power of two which holds all mappings
//        while (capacity < initialCapacity) {
//            capacity <<= 1;
//        }
//
//        table = new Entry[capacity];
//        threshold = (int) Math.min(capacity * loadFactor, MAXIMUM_CAPACITY + 1);
//        useAltHashing = sun.misc.VM.isBooted() &&
//                (capacity >= Holder.ALTERNATIVE_HASHING_THRESHOLD);
//
//        init();  // Give subclass a chance to do its thing.
//
//        // Read the keys and values, and put the mappings in the HashMap
//        for (int i=0; i<mappings; i++) {
//            K key = (K) s.readObject();
//            V value = (V) s.readObject();
//            putForCreate(key, value);
//        }
//    }
//
//    // These methods are used when serializing HashSets
//    int   capacity()     { return table.length; }
//    float loadFactor()   { return loadFactor;   }
//}
